Windmill



M. PLOTKIN Aug. l2, 1941.

WINDMILL Filed Jan. 13, 1940 2 Sheets-Sheet l Aug. v12, 1941.

M. PLOTKIN WINDMILL Filed Jan. 13, 1940 2 Sheets-Sheet 2 Patented Aug. 12, 1941 l UNITED` STATES PATENT (HiFi-CE4 WINDMILL Milton Plotkin, cniagd In. Application January 13, 1940., serial No.Y 313,168

1 Claim.

My object generally stated is to provideimprovements in windmills to the end of improving their construction and rendering them better adapted to perform the function for which they are provided.

Certain of my more specic objects are as follows:

To produce a more compact construction of windmill than hitherto provided, and one which will withstand high wind velocities;

To increase its efciency;

To reduce the cost of such structures;

To provide a construction of Windmill which will be self-starting under all conditions;

To provide against such accumulation of snow in the structure as to interfere with its proper operation;

To provide an improved shape of blade con-- tributing to the self-starting of the windmill; and

To provide a simple, strong and sturdy construction and embodying encircling framework for the operating parts which permits of the supporting of the rotating parts in the most desirable manner.

Referring to the accompanying drawings:

Figure 1V is a view in elevation of a windmill constructed in accordance with my invention.

Figure 2 is a plan view of the structure shown in Fig. 1.

Figure 3 is a plan sectional View taken at the line 3-3 on Fig. 1 and viewedA in the direction of the arrows.

Figure 4 is an enlarged broken sectional View taken at the line 4--4 on Fig. 2 and viewed in the direction of the the arrows; and

Figure 5 a fragmentary sectional view taken at the line 5-5 on Fig. 2 and viewed in the direction of the arrows.

The structure shown as to its general features of construction comprises a framework 5 in which is rotatably mounted a revoluble shield, or guard, 6 partially enclosing a blade, or wing-equipped rotor 1 exposed at one side thereof to the force of the wind; the shield 6 being provided with fins 8 and 9 which cooperate to ensure the proper automatic positioning of the shield, relative to the direction of the wind, regardless of its direction.

` The framework 5 as shown comprises an annular series of uprights IIJ shown as equidistantly spaced apart and six in number and which in the case of the smaller sizes of windmills may be,

by way of example, of angle form as shown, and' in the case of the larger sizes of windmills of fabricated form, these uprights being connected at their upper ends to a rigid ring II shown as seated on` the upper ends of the uprights IU; with the frame-bar I2 extending centrally across the ring II and secured thereto.

The structure thus produced is shown as braced by wire stays I3 connected at their upper ends with the ring I I and the ends of the framebar I2 and anchored at their lower ends in the ground.

The frame-bar I2 affords an upper bearing I4 for a shaft I5 forming a `part of the rotor 1 and by which the power generated by the windmill is transmitted to any device to be driven thereby, as for example an electric generator.

A lower bearing I6 beneath the shield E is provided for the shaft I5, this bearing being rigidly connected with the upper ends of radiating inclined bars I1 the lower ends of which are connected with the lower ends of the uprights Ill, forming a sturdy bearing structure.

The shield Ii as shown is formed of an upper series of spokes I8 radiatingfrom a hub I9- journaled on the shaft I5, and connected at their l outer ends with a ring 20, and a lower series of spokes 2| radiating from a hub 22 journaled on the shaft I5 and connected at their outer ends with a ring 23, the rings 20 and 23 being connected together at intervals'by vertical rods 24, the spokes I8and 2l thus forming an openwork rigid structure.

The lower hub 22 rotates on the bearing I6 between which parts a ball-bearing 25l is preferably interposed to reduce friction in the rotation of the shield 6.

The shield 6 also comprises a vertical arcuate side wall 26 rigidly secured at its upper and lower edges to the rings 20 and 23, and by preference being of a circumferential length slightly less than to present a vertical leading edge 21 and a vertical trailing edge 28.

The shield B carries the tworadially disposed fins or blades 8 and 9 which extend the full height of the shield and are rigidly connected at vertical edges with certain of the rods 24 and at their upper and lower edges to extensions of certain of the spokes I8 and 2|, the extensions of the spokes I8 being shown at I8a. The fins 8 and 9 are spaced apart, preferably about 90, about the circumference of the shield and at equal distances from a diametrical line passing through the leading edge 21 and the axis about which the shield rotates. The n 8 is located at the sidewall-equipped portion of the shield and extends radially outwardly therefrom and is preferably set back a slight distance from the trailing edge 28 of this wall, as for example a distance substantially equal to the Width of the fin as shown; and the n 9 is located at the open side of the shield with its inner edge terminating in substantially the cylindrical plane occupied by the wall 26 as shown.

The rotor 1 comprises an upper and a lower series 29 and 30, respectively, of arms, each series being shown as comprising six arms but the number of which may be varied, the upper arms being directly above the lower arms, and the series of arms being connected at their outer ends with the apex portions of upper and lower hexagonal frames 3| and 32. l

'I'he lower arms 30 are connected, respectively, at their inner ends to a ring 33 surrounding,

and secured to, the shaft I5 and supportedon a..

ball bearing 34 interposed between this ring and the lower bearing 22 of the shield. The upper arms 29 are connected Vattheir inner ends to a ring 35, surrounding,4 and secured to, the. shaft l5.

The blades or vanes of the rotor 1 are represented at 36 being shown as of general rectangular shape, radiating from the shaft I51to which, and to the arms29 and 3l), they are secured. In the particular constructionshown six of the bladesequidistantly spaced apart are provided. However, their number 4may be variedras desired.

The blades 3E extend at their outer vertical edges a slight distance short of the arcuate Wall 26 and project outwardly through the open side of the shield E`Vas5they progressivelymove beyond the leadingedge 21,0f the Wall 26.

The structure also, bypreference, comprises plate-like cover sections 3.7 and.33,vthe upper one 31 being shownas ofhexagonal shape and carried by the rotor-1 `andthelower one 33 of circular shape and carried by the shield '6, certain of the purposes of which are to reduce the likelihood of snow accumulating in the operatingparts and inipairing the proper functioning thereof, andto confine the air impacting the blades at the open side of the shield.

In the operation of the windmill the leading edge 2"! of the shield 5 is held into the Wind, at all times and despite change in direction of the wind, by the action of the wind against the fins 8 and 9. Possibility of the stalling of the shield in a position in which the portion thereof diametrically opposed to the leadingedge -21 faces the Wind,is prevented by reason of the pocketing of the wind in the interior angle 39 between the fin 3 and the trailing edge portion of the wall 26 which exerts a turning movement in excess of that exerted against the iin 9, rotating the shield 6 into a` position in which the wind au'- tomatically rotates theshield into alinement at its leading edge 2l-with the vlrection in which the wind is blowing.

The wind striking theblades Bfat the open side of the shield B beyond its leading edgemZ'l operates to'rotate the, rotor 'l and with it the shaft l5, the wind, as the blades progressively move beyond the diametrical center line of the structure at the open rear side of the shield, escaping freely, and therefore avoiding the building up of pocketed, or back, pressure which would present resistance to the rotation of the rotor.

To avoid failure of starting and to produce the maximum power output, the blades 36 are provided of the form shown, namely, the forward or outward vertical edge 40 of each blade is of greater length than its rear or inner edge and the blade is curved or bowed as represented in the direction `of its length, the blade progressively decreasing in curvature lengthwise of the blade from its outer edge toward its inner edge Which is straight in the lengthwise direction.

By providing the blades 3'3 of this form the force of the wind striking them exerts a greater impetus for driving the rotor 'i in the desired direction than in the opposite direction ensuring the starting of the rotor regardless of the particular position assumed by the rotor when at rest. Furthermore, the provision of the blades as stated minimizes the tendency to produce back pressure and undesirable eddies against the oncoming blade as it passes beyond the leading edge 2 of the shield in the continuing rotation of the rotor.

As will be understood, the provision of the fins 3 and 9 as described which may be made of relatively narrow width, renders the structure comprising the moving parts, Very compact permitting such structure to be housed withinva framing of relatively small dimensions with the advantage of the provision of vertically spaced bearings for the rotating parts, malring for compactness and relatively inexpensive construction while providing for the iirm holding of the operating parts against lateral deflection.

While I have illustrated and described a particular` construction embodying my invention I do not wish to be understood as intending to limit it thereto as the same may be variously modiiied and altered and the invention embodied in other forms of structure without departing from the spirit of my invention.

What ,I claim as new and desire to secure by Letters Patent, is:

A windmill comprising a support, a bladeequipped rotor on said support, a shield for said rotor on said support, said rotor and shield being independently rotatable, said shield having a side wall extending part way only around said shield and presenting a leading edge, and spaced apart iins on said shield at its rear Side disposed at opposite sides of a diametrical line passing through said leading edge and the axis about which said shield rotates, one of said ns being located at said side wall and set in from the trailing edge of said wall to form, with said wall, a pocket, and the other of said fins being remote from said side wall.

MILTON PLOTKIN. 

